The analogue of force is called torque. In the first part of this lab, we will have two torques: frictional torque (which will slow the wheel's spinning) and pulling torque resulting from hanging mass m. We will set up our apparatus as follows:
Axis of rotation: Angular Acceleration about it
Surface Box
Rotating Platform: Moment of Inertia
Black Top Blocking the Photo Gate Beam
Photo Gate
Photo Gate
Rotating Table
Tension
Cylinder with String wound around it
Pulley
Mass m: 200 g
Mass m: with spring
Linear Acceleration
Cylinder with wrapping 4.0 cm
Disk with handle
Height h
The frictional torque will result in some angular acceleration & fr in the absence of hanging mass, which we will measure first. We will then add the hanging mass and determine the net angular acceleration, @net. Based on the sum-of-torques equation on the platform and the sum-of-forces on the mass, we can find the equation for moment of inertia:
mr = (g * ranet) / (@fr + @net)
Finally, we will spin this platform again (without hanging mass), drop a disk (of known mass) on top of it, and determine whether we have conservation of angular momentum in this collision (of sorts).